1. Field of the Invention
The present invention relates generally to Third Generation Partnership Project (3GPP networks) and specifically to packet policy control and charging rules function selection in a 3GPP network.
2. Background Art
An increasingly large number of individuals use portable computing devices, such as laptop computers, personal data assistants (PDAs), smart phones and the like, to support mobile communications. The number of computing devices, and the number of networks that these devices connect to, has increased dramatically in recent years. Similarly, an increasing number of wireless Internet access services have been appearing in airports, cafes and book stores.
As telecommunications technology continues to evolve to meet this ever increasing demand, service providers continue to make investments in state-of-the-art technology in order to remain at the forefront of offerings in the marketplace. However, in order to maximize their return on investment, service providers are constantly challenged to more effectively market their technology offerings by offering richer choices to their subscriber base, and to deliver those choices in a timely and seamless fashion.
The Third Generation Partnership Project (3GPP) long term evolution (LTE) reference architecture defines the use of one or more policy control and charging rules functions (PCRF). As the name implies, PCRF provides policy control decision and flow-based charging control functionalities. For example, the PCRF provides network control regarding service data flow detection, gating, quality of service (QoS), and flow based charging to the policy control enforcement function. In addition, the PCRF may also apply security procedures before accepting service information from an Application Function (AF). Additionally, the PCRF determines how a certain data flow is treated in the policy control enforcement function and ensures that the enforcement function traffic mapping and treatment is in accordance with the user's subscription profile. For example, the PCRF delivers rules around traffic classification, QoS, and charging to the enforcement functions.
The Diameter Routing Agent (DRA) maintains information about user identity, access point name (APN), the user equipment IP address(es) and the selected PCRF for an IP-connectivity access network (IP-CAN) session. The DRA initially allocates a PCRF for a session. Additionally, the DRA may be queried by other network entities that need to change an existing session or establish a new Quality of Service (QoS). The DRA returns the address of the PCRF to the requesting entity.
When the DRA first receives a request for an IP-CAN session, the DRA selects a suitable PCRF for the IP-CAN session and stores the PCRF address. Subsequently, the DRA can retrieve the selected PCRF address according to information carried by the incoming requests from other entities.
Three methods are currently being proposed for accessing a PCRF for an existing session. A redirect DRA is an enhanced form of the Diameter redirect agent functionality. The redirect DRA is used to redirect clients to the appropriate PCRF. A proxy DRA is an enhanced form of the Diameter proxy agent functionality. A proxy DRA is used to forward messages from clients to the appropriate PCRF. Finally, the optimized proxy DRA is a hybrid solution where a proxy is used on IP-CAN session establishment and termination but session modification messages are sent directly to the selected PCRF.
All of these solutions require deployment of additional DRA elements in the network. Furthermore, the DRA messaging introduces additional latency on IP CAN session establishment and termination. The redirect DRA and optimized proxy DRA solutions also have transport connection scaling issues and the proxy DRA solution introduces additional latency to IP CAN session modification exchanges due to the message forwarding.
What is therefore needed is a technique for accessing a PCRF for an existing session that does not introduce additional latency nor pose transport connection scaling issues.